Demon

Demons (also Devils) are an often-thought malevolent race of beings primarily originating from the Demon World.

Behavior
Most demons are generally very selfish, power-hungry, and cruel; often seeking to increase their own power or influence at the expense of either other demons or humans. Very rarely do demons ever show remorse or pity, particularly when regarding humans - whom most demons regard as lesser beings. On the other hand, a few demons can be capable of love and compassion, and decide to live in the human world.

Dante suggests that when a demon becomes selfless or loves, or at least chooses to fight for something other than themselves and their own ambition, they can achieve greater powers. Furthermore, it is suggested that demons can even become figuratively human, at least metaphorically, by learning to feel and express complex emotions such as sadness and love for another, both of which are considered definitive characteristics of human beings.

According to Dante's statements, humans can be, in a way, often worse than demons, by choosing evil out of their own volition, whereas demons are malevolent by nature. Lady makes a similar remark, realizing that there are humans who are just as evil as any demon, as well as demons who are capable of kindness, love and compassion.

Relations with Humans
Because of their inherent beyond-human physical and mystical abilities, most known demons view themselves as superior to humans, and as such wish to rule over them. It is implied that before Sparda's uprising, the demons held dominion over the human world and there were many gates and portals created between the two realms; ever since Sparda sealed off the demon world from the human world, demons have been attempting to regain dominion over the humans.

It is seen that certain demons have disguised themselves as humans and gained an incredible amount of influence in the criminal underworld, the wealthy upper-class, and even close family members and business associates of powerful individuals. However, there are also demons who deny their heritage and go to the human world to live in peace.

Despite the inherent differences and metaphysical inequalities between humans and demons, they are able to mate and produce half-demon offspring which possess the physical and mystical qualities of demons, and the spiritual qualities of humans. Such example is the protagonist Dante, along with his twin Vergil, who were the sons of the human Eva and the demon Sparda. Nero is also of both human and demonic lineage, allegedly of Sparda's bloodline. Hybrid demons are generally greatly despised by full-blooded demons, as they are seen as incomplete and thus a mockery of their power.

Gods
Within the hierarchy of demons lies various demons described as gods. Although some demons are powerful enough to be considered god-like or even mistaken for an actual god such as the likes of Sparda and the Order of the Sword, these kinds of demons are explicitly stated to be gods. Their exact nature isn't defined, they're usually in some sort of leadership position within the Demon World. Although far more powerful than the likes of other demons, they can be slain or sealed away.
 * God of Evil
 * Mundus
 * Argosax
 * Urizen

Hybrids
A hybrid describes a individual with both demonic and human ancestry, usually born from the result of a demon and human relationship, but also those whose relations can be traced to a demon within their ancestry. Because of this, these hybrids innately exhibit enhanced physical prowess and unique abilities thanks to the demon blood within them. With their demon blood, they can transform into their demon state via ability called Devil Trigger.

Despite the potential for power, however, many demons looks upon hybrids with scorn and label them no more better than that of a human or simply half-breeds. Some human-demon hybrids include:

Half-human, half-demon

 * Dante
 * Vergil

3/4 Human, 1/4 Demon

 * Nero

Unknown ratio

 * Matier

Artificial Demons
Demons that are created by humans using various methods, typically through a combination of magic and science.

Order of the Sword
The Ascension Ceremony is a method to give humans both demonic power and forms that are used by the Order of the Sword. The ceremony has varying effects, giving the participant a transformation similar to Devil Trigger, permanently transform them into a demon, or give them demonic power.

Ascension Ceremony demons vary in behavior that ranges from ordanary humans with free will, to robotic machines. According to the novelization, strong-willed individuals retain their free will and independent power, while those of weak will who undergo the Ascension Ceremony lose their free will entirely and become feral, with their human souls becoming completely subverted or devoured by the demon soul possessing them. Artificial demons created through the Ascension ceremony include:
 * Credo
 * Agnus
 * Sanctus
 * Alto Angelos
 * Bianco Angelos

Agnus uses another, unknown method to create demons by magically combining various animals with weapons. Among them are:
 * Basilisk
 * Cutlass
 * Gladius

Arius' Secretary demon
Secretaries are artificially-created female demons used by Arius and the Uroboros Corporation in which are similar in appearance and capabilities to that of a human hybrid despite being fully demon. They're capable of retaining both a human appearance and transformation via the Devil Trigger abilities. These demons have the notable characteristics of the form of beautiful, dark-skinned women with red hair. Arius considers Secretaries to be similar to mannequins, and at one point were subject to "defects" that made them unsuitable for Arius to use.
 * Lucia
 * Secretary

Abilities
Demons are hierarchical in nature in a manner similar to pack animals or hive insects. The abilities of demons are often greatly varied among the middle and higher ranks. Demons usually seem to possess powers that are based on a certain element, such as fire, ice or lightning. Demons also come in a wide array of shapes and sizes, are generally considerably stronger and tougher than both humans and earthly animals in order to survive and thrive within the otherworldly and often harsh terrain of the Underworld, and are able to perform superhuman and supernatural feats with relative ease. The most prominent ability displayed by almost every demon seen in the series thus far is immortality; demons are known to live for over two thousand years without being subject to old age or death. In Devil May Cry 2, Arius sought this power by summoning the powers of Argosax.

After a demon is killed, it is possible for its soul and power to be turned into a weapon known as a "Devil Arm", though, as with the Sword of Sparda, a demon does not necessarily have to die to create a weapon from its power. Some demons willingly give their souls in battle if their opponent proves their strength.

Even though demons possess abilities beyond that of any human, that does not prevent humans from being able to fight and even kill a demon. Humans with enough skill to do so seem to be very rare, but those that do often become Devil Hunters.

Trivia

 * In Devil May Cry, Dante states that demons do not possess souls. However, this is proved untrue in Devil May Cry 4, as Bianco Angelos are powered by either a human or demonic soul. As such, this assumption could be merely a moral prejudice on Dante's part from his traumatic experiences in his youth at the hands of demons. It is likely, however, that he meant it as a figure of speech rather than a literal meaning.
 * Additionally, Devil May Cry 4 was not written by the same people who wrote Devil May Cry, which could explain this small change.